.appwrap {
    width: 100%;
    height: 100%;
    display: flex;
    overflow: hidden;
}
.left {
    width: 120px;
    height: 100%;
    overflow-y: auto;
    background-color: pink;
}
.right {
    flex: 1;
    background-color: yellow;
    overflow-y: auto;
}
.h3 {
    width: 100%;
    height: 40px;
    line-height: 40px;
    text-align: center;
}
/* 防止类名一样造成样式冲突的 */